The Fuse from Mio is one of the best ideas we've seen this year. While heart rate straps can be a pain to wear around your chest, the Fuse incorporates a more comfortable wrist strap that's just as accurate. It's also Bluetooth capable and syncs with most bike computers and apps, including Garmin, Cateye, MapMyRide and Strava.
What we liked best was the vibration motor that alerts you as you move through the heart rate zones. In addition to this feature, there's a small LED that changes colors depending on which zone you're in. This makes it easy to stay in your target heart rate zone without having to keep your eyes glued to your bike computer—which is definitely safer out on the road.
Since the Fuse is also an activity tracker, there's plenty of other features, too, such as a step counter, calorie calculator, pace and distance metrics, and a goal tracker. You can also keep track of all this on the Mio Global app, which is customizable depending on which activities or metrics you'd like to keep track of. Though we used the Fuse mostly as a heart rate alternative, the activity tracking features were so plentiful we ended up wearing it throughout the day instead of a watch.